Hello,

If no codes are present than this would be a mechanical issue - I am assuming. I would treat each issue separately at first. If the mast won't lower, either maybe a bearing//roller could be obstructing the path. If the mast cannot tilt, maybe an oil pressure blockage. I would use the relief valve on the oil control valve to see if it lowers when you relieve pressure.

Could be an issue with oil pressure return. So inspect all return lines from the tilt cylinders and mast. If no obstructions and are allow full return, than look into actual oil control valve.